This invention relates to a package for a flat, angular product such as a chocolate bar and includes a wrapper material on which a longitudinal sealing seam is provided that extends on one of the large faces of the product and has further sealing seams at the two opposite short end faces.
In known packages of the above-outlined type, such as disclosed, for example, in Swiss Patent No. 254,978, the wrapper material is an aluminum foil provided on its inner side with a thermoplastic sealing layer. The longitudinal fin seam serves both as a hermetic closure and as a warranty (safety) seal. The two flaps forming the longitudinal fin seam are of equal width and are folded flat onto the top side of the package. The two closures at the opposite short end faces of the item are folded over their two respective flaps onto the underside. This means that the fin seam and the closures interrupt the large package faces which are usually intended to carry promotional messages. Therefore, it is customary to complement the package with a second, paper wrapper. Such a procedure requires a more complex packaging machine, apart from additional packaging material.
German Auslegeschrift (published examined application) No. 1,030,247 discloses an outer paper wrapper for a package of the above-disclosed type wherein on the rear side of the chocolate bar first the short end closures and thereafter the remaining two longitudinal flaps are folded down. Such an overlapping mode of packaging is not adapted for forming sealing seams because such sealing seams must be fin seams. A hermetic seal for the product can therefore not be obtained.
U S. Pat. No. 3,124,298 discloses a package having a longitudinal fin seam which--although not utilized for flat angular items--stands up perpendicularly from a face of the package and thus interrupts the large face of the package making it unadapted for use to display promotional messages thereon.
Swiss Patent No. 655,475 also discloses a wrapper foil provided with an inner sealing coating which, under the formation of a longitudinal fin seam and two end closures is folded about the product. Of the two flaps which form the longitudinal fin seam, the second flap projects, in a mid zone, beyond the edge of the first flap and is, after folding over two longitudinal edges, secured to the underface of the package with adhesive dots. As a result, this type of package has both on its upper face and on its under face a large, uninterrupted surface adapted to carry promotional messages. It is, however, a disadvantage of such a package that for the packaging previously cut individual wrapper sheets are needed so that a high packaging output with the packing machines is not possible.